The metallic materials used for manufacturing heavy-duty components must satisfy stringent quality standards. Such components include, for example, rapidly rotating disks of turbine or compressor stages of a gas turbine that propels an airplane. Blades are attached to these disks. In such a material, flaws may occur that are caused by, in particular, the manufacturing process of the material. These flaws include casting bubbles, pores, inclusions, heat-treatment cracks, and welding cracks. Methods and devices are needed for detecting such flaws and quantifying the detectability of flaws.
The use of ultrasonics for non-destructive material testing is described in “Dubbel—Taschenbuch für den Maschinenbau” (Dubell—Pocket Book of Mechanical Engineering), 20th edition, Springer Publishing House, 2001, E33 and S87.
Test specimens and calibration specimens are used for the reliable and comparable testing of a component with the aid of ultrasonics. Conventionally, blocks having flat-top bores or cross bores are provided for this. These blocks are mostly made out of the same material as the part to be manufactured. Therefore, neither the shape and dimensions, nor the reflection characteristic and reradiation characteristic of real flaws are realistically described.
Japanese Published Patent Application No. 2002-048773 describes a device for calibrating an ultrasonic testing device. The method may be used for a testing device having one probe and for one having two probes. Several calibration holes are introduced into a welded component in a particular manner. The probe(s) are applied or attached to the part and at specific angles to one another, and a characteristic curve for the distance, spacing or interval between distance and amplitude is generated.
In U.S. Pat. No. 5,670,719, a system is described which ascertains the resolution of medical ultrasonic testing devices. The system predicts the local wounds or tumors in the tissue of a human that the testing device detects. A phantom container simulates human tissue. Wounds and tumors are simulated in several layers with the aid of scattering particles. It is determined, which particles are detected and which are not.